So I came on to Onigiri and I can't see anyone on the game. If I'm invited to a party and I accept I can see the people in the party but still no one in the game. Is there a player visibility setting I accidentally triggered? Please help. Me and my friend tried to fix it but she also doesn't know whats going on ;-;

Yes, that is most likely what happened. You can increase the player count display in the Settings. You can also adjust the partner character display count there too.